Cable assembly with equalizer board

ABSTRACT

An electrical cable assembly  1  comprising: a housing  2,  electrical contacts  3  in the housing  2  connected to a circuit board  4,  multiple conductors  5  of an electrical cable  6  connected to the circuit board  4,  signal conditioning circuitry  7  on the circuit board  4,  the circuitry  7  being interposed between the electrical contacts  3  and the conductors  5,  and an insulating holder  8  mounted on the circuit board  4,  the contacts  3  extending on the holder  8,  and the holder  8  being mounted in a cavity in the housing  2.

This application claims the benefit of U.S. Provisional Application Ser.No. 60/009,488, filed Dec. 21, 1995 and this application is acontinuation of Reissue Patent RE 37,893, filed Jun. 16, 2000 and issuedon Oct. 22, 2002, the subject matter of each of which is hereinincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to an electrical cable assembly, and moreparticularly, to an electrical cable assembly in which signalconditioning circuit elements terminate multiple electrical cableconductors.

BACKGROUND OF THE INVENTION

An electrical cable assembly as disclosed in U.S. Pat. Nos. 5,358,426and 4,023,879, comprises, an electrical cable with multiple electricalconductors, and a housing attached to the cable, and electrical contactsin the housing. For a cable assembly without signal conditioning circuitelements, the electrical contacts connect directly to respective cableconductors. For a cable assembly with signal conditioning circuitelements, such as resistors, capacitors and inductors, the circuitelements are mounted in the housing, and are connected with electricalcontacts in the housing. When the circuit elements are individual, ordiscrete, circuit elements, each must be individually mounted in thehousing, and individually connected to electrical contacts. Time isexpended to incorporate individual circuit elements into the cableassembly. Further time is expended to connect individual circuitelements with cable conductors and electrical contacts.

A problem to be solved is to improve the manner in which signalconditioning circuit elements are incorporated into a housing andconnected to electrical contacts and multiple cable conductors.

SUMMARY OF THE INVENTION

According to the invention, a cable assembly incorporates a circuitboard with signal conditioning circuitry. The signal conditioningcircuitry on a circuit board replaces individual circuit elements. Thecircuit board is a feature that reduces the time required to incorporatesignal conditioning circuit elements with the cable assembly, andreduces the time required for connection of the circuit elements withthe electrical contacts and with the cable conductors. Circuit elementsthat provide signal conditioning can be mounted on the circuit board,and circuitry on the circuit board can be aligned with and joined withelectrical contacts and cable conductors. The electrical contacts areconnected to the circuit board, and multiple conductors of an electricalcable are connected to the circuit board. Thus, a feature of theinvention resides in a circuit board to incorporate signal conditioningcircuitry in a cable assembly.

An advantage of the invention resides in a cable assembly having ahousing that is constructed for alignment of a circuit board relative toelectrical contacts and multiple cable conductors, which improves thetime expended for performing connection of signal conditioning circuitrywith the contacts and the cable conductors.

DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described, by way of example,with reference to the accompanying drawings, according to which:

FIG. 1 is a top view of a cable assembly;

FIG. 2 is a side view of the cable assembly shown in FIG. 2;

FIG. 3 is a section view of an electrical cable;

FIG. 4 is a top view of a housing comprising a portion of the cableassembly shown in FIG. 1;

FIG. 5 is a side view of the housing as shown in FIG. 4;

FIG. 6 is a side view partially in section of the housing as shown inFIG. 5;

FIG. 7 is a bottom view of the housing as shown in FIG. 4;

FIG. 8 is an end view of the housing as shown in FIG. 7;

FIG. 9 is a front view of a holder comprising a portion of the cableassembly as shown in FIG. 1;

FIG. 10 is a top view of the holder as shown in FIG. 9;

FIG. 11 is a section view of the holder as shown in FIG. 10;

FIG. 12 is an end view of the holder as shown in FIG. 9.

FIG. 13 is atop view of electrical contacts on a removable carrierstrip;

FIG. 14 is an edgewise view of one of the contacts as shown in FIG. 13;

FIG. 15 is a view similar to FIG. 14 and illustrating a holder incombination with multiple contacts as shown in FIG. 13;

FIG. 16 is a side view of a conducting shell comprising a portion of anelectrical shield;

FIG. 17 is a top view of the shell as shown in FIG. 16;

FIG. 18 is a side view of the shell as shown in FIG. 17;

FIG. 19 is a section view of a channel portion of the shell as shown inFIG. 18;

FIG. 20 is a top view of a top layer of a circuit board;

FIG. 21 is a top view of a middle layer of the circuit board as shown inFIG. 20; and

FIG. 22 is a bottom view of a bottom layer of the circuit board as shownin FIG. 20.

DETAILED DESCRIPTION

With reference to the FIGS. 1-3 an electrical cable assembly 1comprises, a housing 2, electrical contacts 3 (see FIGS. 13-15) in thehousing 2 connected to a circuit board 4, multiple conductors 5 of anelectrical cable 6 connected to the circuit board 4, signal conditioningcircuitry 7 on the circuit board 4, the circuitry 7 being interposedbetween the electrical contacts 3 and the conductors 5, and aninsulating holder 8 (see FIGS. 9-12) mounted on the circuit board 4, thecontacts 3 extending on the holder 8, and the holder 8 being mounted ina cavity 43 in the housing 2.

The circuit board 4 is of multi-layer circuit board construction,comprising: a flat insulating substrate 9 having an upper layer 10, acentral layer 11 and a bottom layer 12 (see FIGS. 20-22). The centrallayer 11 is separated from the other layers 10, 12 by insulatingmaterial of the substrate 9.

The central layer 11 comprises, a conducting ground plane 13, referencedto electrical ground, with plating lined apertures 14 (also known asvias) extending through the central layer 11. These plating linedapertures 14 extend through the upper layer 10 and the bottom layer 12.In the apertures 14, the plating establishes electrical connections onthe upper layer 10 and the lower layer 12 to the ground plane 13. Signalconditioning circuitry 7 on the upper layer 10 is in the form ofmultiple conducting pads 15, of square shape, and multiple relativelynarrow circuit paths 16 interconnecting various conducting pads 15 andvarious plating lined apertures 14. Each of the pads 15 is identifiedwith an impedance symbol, R or L or C to indicate electrical elementsthat provide signal conditioning, which satisfies requirements ofindustry technical standard documents, ANSI X3TI 1/FC-0, ANSI X3TIIspecification and ANSI X3T10.1 for a High Speed Serial Data Connector.The elements vary with cable construction, data rate and length of thecable assembly 1, and have the following typical values:

-   -   R1=75 Ohm R7=37 Ohm    -   R2=75 Ohm R8=75 Ohm    -   R3=150 Ohm L1=390 nH    -   R4=75 Ohm C1=33 pF    -   R5=37 Ohm C2=33 pF    -   R6=150 Ohm

The elements can be constructed of discrete or individual circuitelements, not shown, that are attached to the pads by a solderingoperation. Alternatively, the impedances can be of planar microstripconstruction fabricated by known microstrip making processes.

The upper layer 10 of the signal conditioning circuitry 7 furthercomprises, an array of three conducting pads 17 along an edge 18 of thecircuit board 4 for connection to respective electrical contacts 3.

The lower or bottom layer 12 of the signal conditioning circuitry 7comprises, an array of three conducting pads 17 along the edge 18 of thecircuit board 4 for connection to respective electrical contacts 3, anarray of six conducting pads 19 along another edge 20 of the circuitboard 4 for connection to respective cable conductors 5, and electricalcircuit paths 16 interconnecting various pads 19 and plating linedapertures 14. The cable conductors 5 can extend from separate electricalcables or can extend together from a single electrical cable 6 as shown(see FIG. 3).

Each of the electrical contacts 3 has a construction as shown (see FIGS.13-15). Each contact 3 is stamped and formed from a strip of metalhaving a plane of thickness. Each contact 3 extends from a carrier strip21, and is subsequently severed from the carrier strip 21. A side view(see FIG. 14) shows a plane of thickness of the contact 3 edgewise, withvarious bends 22 along the length of the contact 3.

An insulating holder 8 is of unitary molded construction. Projecting,tapered latch fingers 23 project from exterior ends 24 of the holder 8(see FIGS. 9-10). A row of spaced apart passages 25 extend through afront end 26 and a rear end 27 of the holder 8 (see FIGS. 9-11). Arecess 29 in the rear end 27 intercepts each of the passages 25. Thepassages 25 extend beside the recess 29 and communicate with the recess29.

Each of the contacts 3 fits with a friction fit in any one of thepassages 25. When the contacts 3 are mounted in respective passages 25,the contacts 3 extend through the holder 8 from front end 26 to the rearend 27. The contacts 3 project into the recess 29.

A front edge 30 of the circuit board 4 is received in the recess 29 witha friction fit (see FIG. 15). The holder 8 aligns respective contacts 3with corresponding pads along the front edge. The rear ends of thecontacts 3 project beyond the rear end of the holder 8 and overliecorresponding pads that also project beyond the rear end of the holder8. Both the contacts 3 and the pads are exposed for visible inspection,and to effect joining of the contacts 3 with the pads. The contacts 3can be joined to the overlaid pads by solder. For example, the pads canbe coated with solder that has solidified prior to being overlaid by thecontacts 3. The solder can be reflowed by the application of heat tojoin the contacts 3 and the pads. The joined pads and contacts 3 can beinspected visually for defective solder joints. The circuit board 4 isfurther held by the holder 8 for joining cable conductors 5 to the padson the holder 8. As shown in FIG. 3 cable conductors 5 extend from onecable 6, or, alternatively, multiple cables, to respective pads 17 onboth sides of the circuit board 4. The cable conductors 5 are joined bysolder to the pads 19.

The housing 2 is of unitary construction, molded from an insulatingmaterial. A latch arm 31 is a cantilever beam joined at a front end 32to a top side 33 of the housing 2 (see FIGS. 4-5). The latch arm 31extends at an outward incline from the front end 32 toward the rear 34of the housing 2. A front mating end 35 of the housing 2 has an opening36 that opens laterally to a bottom side 37 of the housing 2 (see FIG.6). Laterally beside the opening 36 a row of contact receiving channels38 extend recessed along a tongue 39 on the housing 2. The channels 38have narrower front portions 40 to receive the narrower tips 41 of thecontacts 3 (see FIGS. 7 and 14). The opening 36 fully exposes thechannels 38 through the bottom side 37, which enables inspection of thecontacts 3 for proper registration along the channels 38. This advantageis particularly important when the contacts 3 have narrow tips 41 thatare susceptible to damage.

In the interior of the housing 2, the channels 38 extend through a frontwall 42 of a cavity 43. The cavity 43 has a width that extends acrossall of the channels 38. The width extends to opposite sides 44 of thehousing 2. Circuit board receiving grooves 45 are recessed in the sides44 of the housing 2, the grooves 45 opening into the cavity 43.Resiliently deflectable latch fingers 46 project into the cavity 43 andintercept the grooves 45. Each latch finger 46 is integral with aremainder of the housing 2. Each latch finger 46 is constructed by aslit 47 through the housing 2 along three sides of the finger 46, whichdefines the flange 46 as a resilient cantilever beam. A rampedprojection 48 on each tip of the latch fingers 46 projects into thecorresponding groove 45.

The grooves 45 and the cavity 43 extend through a rear 34 of the housing2. A first window 50 provides an open bottom side 37 of the housing 2.The window 50 spans the width of the cavity 43 and communicates with theopening 36. The opening 36 exposes the interior of the housing 2 whenthe housing 2 is viewed from the bottom side 51. The opening 36 exposesthe lengths of the channels 38 when the housing 2 is viewed from thebottom side 51. The first window 50 extends from the front wall 42 ofthe cavity 43 to the rear 49 of the housing 2. A second window 52provides an open top side 53 of the housing 2. The second window 52spans the width of the cavity 43, and extends through the rear 49 of thehousing 2 and extends forwardly to an end wall 54. The second window 52is shorter front to rear than the first window 50.

Assembly of the housing 2 with the circuit board 4, the holder 8 and thecontacts 3 will now be described. The contacts 3 and the circuit board 4have been mounted to the holder 8, as described herein. The contacts 3project forwardly of the holder 8 and are aligned with correspondingchannels 38, as the holder 8 is inserted into the rear of the housing 2.The projecting latch fingers 23 on the holder 8 are aligned with thegrooves 45. The holder 8 is moved forwardly relative to the housing 2.The latch fingers 23 on the holder 8 slide forwardly along the grooves45 to deflect outwardly that latch fingers 46 on the housing 2. Once thelatch fingers 23 on the holder 8 pass the deflected latch fingers 46 onthe housing 2, the latch fingers 46 on the housing 2 deflect resilientlyand return to their prior positions, whereby they lock against the latchfingers 23 on the holder 8 to resist rearward movement of the holder 8.The front end 26 on the holder 8 faces the front wall 42 on the housing2 to resist movement farther forward. The contacts 3 are moved forwardlyinto and along respective channels 38. The connections of the contacts 3and the cable conductors 5 with the circuit board 4 are visible forinspection through the respective windows 50, 52. The conductive pads17, 19 on the circuit board 4 face respective open sides of the housing2. The contacts 3 and the conductors 5 of the cable 6 overlie respectiveconductive pads 17, 19 and are viewed through the open sides forregistration of the contacts 3 with the pads 17, and for registration ofthe cable conductors 5. The circuit board 4 has its edges held in thegrooves 45.

The circuit board 4 is held centrally in the housing 2 with spacious airgaps 55 on both sides of the circuit board 4. The air gaps 55 aresufficient to prevent electrical shorting to the unprotected circuitboard 4 that is exposed by the windows 50, 52. A conductive shield 56comprised of two, sheet metal shells 57, 57 that cover the windows 50,52 and encircle the housing 2. Further details of the shield 56 and theshells 57, 57 are disclosed in U.S. patent application Ser. No.08/008,926, Filed Jan. 26, 1993, incorporated herein by reference. Theshells 57,57 are identical, and extend rearwardly beyond the rear 49 ofthe housing 2. Channels 59 on a rear of both shells 57,57 encircle andenclose on an electrical cable 6, providing a strain relief 60 thatgrips the cable 6. The application of a tensile force on the cable 6will be absorbed by the strain relief 60 to prevent a transfer oftensile force onto the connections of the cable conductors 5 and thecircuit board 4.

An insulating overmold 61 covers the shield 56 and the cable 6. Theovermold 61 is molded in situ to cover a rear of the shield 56 and toencircle the cable 6 and provide a bending strain relief 58.

An advantage of the invention resides in a cable assembly 1 having ahousing 2 that is constructed for alignment of a circuit board 4relative to electrical contacts 3 and multiple cable conductors 5, whichimproves the time expended for performing connection of signalconditioning circuitry 7 with the contacts 3 and the cable conductors 5.

1. An electrical cable assembly comprising: multiple conductors of anelectrical cable connected to circuitry on a circuit board, multipleelectrical contacts in registration with respective conductive pads ofthe circuitry, an insulating holder holding the circuit board and theelectrical contacts, an insulating housing receiving therein the holderand the electrical contacts and the circuit board, a window providing anopen side of the housing, the contacts and the pads being exposedthrough the open side for inspection of the registration of the contactswith the pads.
 2. An electrical cable assembly as recited in claim 1,and further comprising: a conductive shield encircling the housing andcovering the window.
 3. An electrical cable assembly as recited in claim2 wherein, a strain relief on the shield grips the cable.
 4. Anelectrical cable assembly as recited in claim 1, and further comprising:another window providing a second open side of the housing, the cableconductors and the circuitry being exposed through the second open sidefor inspection of connections of the cable conductors with thecircuitry.
 5. An electrical cable assembly as recited in claim 4, andfurther comprising: a conductive shield encircling the housing andcovering both the window and said another window.
 6. An electrical cableassembly as recited in claim 5 wherein, a strain relief on the shieldgrips the cable.
 7. An electrical cable assembly as recited in claim 1wherein, tips of the contacts project from the holder and extend intothe housing.
 8. An electrical cable assembly comprising: multipleelectrical contacts and multiple conductors of an electrical cableconnected to respective conductive pads of circuitry on a circuit board,an insulating holder holding the circuit board and the electricalcontacts, an insulating housing receiving therein the holder and theelectrical contacts, the circuit board being held in the housing, andwindows in open sides of the housing exposing for inspection thecontacts and the conductors overlying respective conductive pads of thecircuitry.
 9. An electrical cable assembly as recited in claim 8wherein, the holder and the contacts and the circuit board are receivedalong a cavity that extends to a rear of the housing, and the holder andthe housing latch together to resist rearward movement of the holder.10. An electrical cable assembly as recited in claim 8, and furthercomprising: a conductive shield encircling the housing and covering thewindows.
 11. An electrical cable assembly as recited in claim 8 wherein,tips of the contacts project from the holder and extend into thehousing.
 12. An electrical cable assembly comprising: multipleelectrical contacts and multiple conductors of an electrical cableconnected to respective conductive pads of circuitry on a circuit board,an insulating holder holding the circuit board and the electricalcontacts, an insulating housing receiving therein the holder and theelectrical contacts, the circuit board being held in the housing, awindow providing an open side of the housing, the cable conductors andthe circuitry being exposed through the open side for inspection ofconnections of the cable conductors with the circuitry.
 13. Anelectrical cable assembly as recited in claim 12, and furthercomprising: a conductive shield encircling the housing and covering thewindow.
 14. An electrical cable assembly as recited in claim 12 wherein,tips of the contacts project from the holder and extend into thehousing.
 15. A method of assembling an electrical connector assemblycomprising: providing a circuit board; connecting electrical contacts tothe circuit board; providing a housing having a top side and oppositesides that define a cavity in the housing, the cavity extending betweenthe opposite sides, the housing having a front mating end with anopening therein that opens laterally to a bottom side of the housing;recessing grooves into the opposite sides of the housing with thegrooves open into the cavity extending between the opposite sides,wherein the grooves and the cavity extend to a rear end of the housing;and inserting a contact holder, electrical contacts and the circuitboard at the rear end of the housing into the grooves and cavity untilthe circuit board is proximate the front mating end of the housing. 16.The method of claim 15, further comprising providing signal conditioningcircuitry on the circuit board for conditioning high speed serial datasignals carried over an electrical cable.
 17. The method of claim 15,further comprising mounting signal conditioning circuitry on the circuitboard before inserting the circuit board into the grooves.
 18. Themethod of claim 15, further comprising: inserting the contact holder andelectrical contacts through the rear end of the housing into the groovesprior to inserting the circuit board into the housing, wherein theelectrical contacts are connected to the circuit board after the circuitboard is inserted into the housing.
 19. The method of claim 15, furthercomprising: providing conductive pads on the circuit board;interconnecting the conductive pads with narrow circuit paths on thecircuit board; and attaching signal conditioning circuitry to at leastone of the conductive pads and the circuit paths.
 20. The method ofclaim 15, further comprising: soldering circuit elements to the circuitboard to provide signal conditioning.
 21. The method of claim 15,further comprising mounting electrical contacts to the circuit boardbefore inserting the circuit board into the grooves.
 22. The method ofclaim 15, further comprising: mounting a holder to the circuit board;and mounting contacts to the holder.
 23. The method of claim 15, furthercomprising providing a holder configured to be mounted to contacts andthe circuit board, the holder including latch fingers; and inserting thelatch fingers into the grooves at the rear end of the housing beforeinserting the circuit board.
 24. The method of claim 15, furthercomprising connecting an electrical cable to the circuit board.
 25. Amethod of assembling an electrical connector assembly comprising:providing a circuit board; providing a housing having a top side andopposite sides that define a cavity in the housing, the cavity extendingbetween the opposite sides, the housing having a front mating end withan opening therein that opens laterally to a bottom side of the housing;recessing grooves into the opposite sides of the housing with thegrooves open into the cavity extending between the opposite sides,wherein the grooves and the cavity extend to a rear end of the housing;inserting the circuit board at the rear end of the housing into thegrooves and cavity until the circuit board is proximate the front matingend of the housing; and recessing a row of channels along a tongue onthe housing, the tongue being located beside the opening in the frontmating end.
 26. The method of claim 25, further comprising providingsignal conditioning circuitry on the circuit board for conditioning highspeed serial data signals carried over an electrical cable.
 27. Themethod of claim 25, further comprising: inserting a contact holder andelectrical contacts through the rear end of the housing into thegrooves; and connecting the electrical contacts to the circuit board.28. The method of claim 25, further comprising: providing conductivepads on the circuit board; interconnecting the conductive pads withnarrow circuit paths on the circuit board; and attaching signalconditioning circuitry to at least one of the conductive pads and thecircuit paths.
 29. The method of claim 25, further comprising: mountinga holder to the circuit board; and mounting contacts to the holder. 30.The method of claim 25, further comprising providing a holder configuredto be mounted to contacts and the circuit board, the holder includinglatch fingers; and inserting the latch fingers into the grooves at therear end of the housing before inserting the circuit board.
 31. Anelectrical connector assembly, comprising: a circuit board with contactson at least one end thereof; a housing having a top side and oppositesides that define a cavity in said housing, said cavity extendingbetween said opposite sides, said housing having a front mating end withan opening therein that opens laterally to a bottom side of saidhousing, said opposite sides having grooves recessed therein, saidgrooves opening into said cavity, said grooves and cavity extending to arear end of said housing, said circuit board being inserted into saidgrooves and said cavity at said rear end of said housing until saidcircuit board is proximate said front mating end; and a holder securingsaid contacts to said circuit board, said holder being inserted intosaid grooves in said opposite sides of said housing.
 32. The electricalconnector assembly of claim 31, further comprising signal conditioningcircuitry mounting on said circuit board, said signal conditioningcircuitry being set to condition high speed serial data signals carriedover an electrical cable.
 33. The electrical connector assembly of claim31, further comprising signal conditioning circuitry mounted on saidcircuit board.
 34. The electrical connector assembly of claim 31,further comprising an electrical cable connected to said circuit board.35. An electrical connector assembly comprising: a circuit board withcontacts on at least one end thereof; a housing having a top side andopposite sides that define a cavity in said housing, said cavityextending between said opposite sides, said housing having a frontmating end with an opening therein that opens laterally to a bottom sideof said housing, said opposite sides having grooves recessed therein,said grooves opening into said cavity, said grooves and cavity extendingto a rear end of said housing, said circuit board being inserted intosaid grooves and said cavity at said rear end of said housing until saidcircuit board is proximate said front mating end, and said housinghaving a row of channels recessed along a tongue of said housing, saidtongue being located beside said opening in said front mating end. 36.The electrical connector assembly of claim 35, further comprising signalconditioning circuitry mounting on said circuit board, said signalconditioning circuitry being set to condition high speed serial datasignals carried over an electrical cable.
 37. The electrical connectorassembly of claim 35, further comprising signal conditioning circuitrymounted on said circuit board.
 38. The electrical connector assembly ofclaim 35, further comprising an electrical cable connected to saidcircuit board.
 39. The electrical connector assembly of claim 35,further comprising a holder securing said contacts to said circuitboard, said holder being inserted into said grooves in said oppositesides of said housing.